sys/vfs/hammer2/hammer2_inode.c

   1 /*
   2  * Copyright (c) 2011-2013 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35 #include <sys/cdefs.h>
  36 #include <sys/param.h>
  37 #include <sys/systm.h>
  38 #include <sys/types.h>
  39 #include <sys/lock.h>
  40 #include <sys/uuid.h>
  41
  42 #include "hammer2.h"
  43
  44 RB_GENERATE2(hammer2_inode_tree, hammer2_inode, rbnode, hammer2_inode_cmp,
  45              hammer2_tid_t, inum);
  46
  47 int
  48 hammer2_inode_cmp(hammer2_inode_t *ip1, hammer2_inode_t *ip2)
  49 {
  50         if (ip1->inum < ip2->inum)
  51                 return(-1);
  52         if (ip1->inum > ip2->inum)
  53                 return(1);
  54         return(0);
  55 }
  56
  57 hammer2_inode_t *
  58 hammer2_inode_lookup(hammer2_pfsmount_t *pmp, hammer2_tid_t inum)
  59 {
  60         hammer2_inode_t *ip;
  61
  62         if (pmp) {
  63                 spin_lock(&pmp->inum_spin);
  64                 ip = RB_LOOKUP(hammer2_inode_tree, &pmp->inum_tree, inum);
  65                 if (ip)
  66                         hammer2_inode_ref(ip);
  67                 spin_unlock(&pmp->inum_spin);
  68         } else {
  69                 ip = NULL;
  70         }
  71         return(ip);
  72 }
  73
  74 /*
  75  * Adding a ref to an inode is only legal if the inode already has at least
  76  * one ref.
  77  */
  78 void
  79 hammer2_inode_ref(hammer2_inode_t *ip)
  80 {
  81         atomic_add_int(&ip->refs, 1);
  82 }
  83
  84 /*
  85  * Drop an inode reference, freeing the inode when the last reference goes
  86  * away.
  87  */
  88 void
  89 hammer2_inode_drop(hammer2_inode_t *ip)
  90 {
  91         hammer2_mount_t *hmp;
  92         hammer2_inode_t *pip;
  93         hammer2_chain_t *chain;
  94         u_int refs;
  95
  96         while (ip) {
  97                 refs = ip->refs;
  98                 cpu_ccfence();
  99                 if (refs == 1) {
 100                         /*
 101                          * Transition to zero, must interlock with
 102                          * the inode inumber lookup tree (if applicable).
 103                          *
 104                          * NOTE: The super-root inode has no pmp.
 105                          */
 106                         if (ip->pmp)
 107                                 spin_lock(&ip->pmp->inum_spin);
 108
 109                         if (atomic_cmpset_int(&ip->refs, 1, 0)) {
 110                                 KKASSERT(ip->topo_cst.count == 0);
 111                                 if (ip->flags & HAMMER2_INODE_ONRBTREE) {
 112                                         atomic_clear_int(&ip->flags,
 113                                                      HAMMER2_INODE_ONRBTREE);
 114                                         RB_REMOVE(hammer2_inode_tree,
 115                                                   &ip->pmp->inum_tree,
 116                                                   ip);
 117                                 }
 118                                 if (ip->pmp)
 119                                         spin_unlock(&ip->pmp->inum_spin);
 120
 121                                 hmp = ip->hmp;
 122                                 ip->hmp = NULL;
 123                                 pip = ip->pip;
 124                                 ip->pip = NULL;
 125                                 chain = ip->chain;
 126                                 ip->chain = NULL;
 127                                 if (chain)
 128                                         hammer2_chain_drop(chain);
 129
 130                                 /*
 131                                  * We have to drop pip (if non-NULL) to
 132                                  * dispose of our implied reference from
 133                                  * ip->pip.  We can simply loop on it.
 134                                  */
 135                                 kfree(ip, hmp->minode);
 136                                 ip = pip;
 137                                 /* continue with pip (can be NULL) */
 138                         } else {
 139                                 if (ip->pmp)
 140                                         spin_unlock(&ip->pmp->inum_spin);
 141                         }
 142                 } else {
 143                         /*
 144                          * Non zero transition
 145                          */
 146                         if (atomic_cmpset_int(&ip->refs, refs, refs - 1))
 147                                 break;
 148                 }
 149         }
 150 }
 151
 152 /*
 153  * Get the vnode associated with the given inode, allocating the vnode if
 154  * necessary.  The vnode will be returned exclusively locked.
 155  *
 156  * The caller must lock the inode (shared or exclusive).
 157  *
 158  * Great care must be taken to avoid deadlocks and vnode acquisition/reclaim
 159  * races.
 160  */
 161 struct vnode *
 162 hammer2_igetv(hammer2_inode_t *ip, int *errorp)
 163 {
 164         hammer2_inode_data_t *ipdata;
 165         hammer2_pfsmount_t *pmp;
 166         struct vnode *vp;
 167         ccms_state_t ostate;
 168
 169         pmp = ip->pmp;
 170         KKASSERT(pmp != NULL);
 171         *errorp = 0;
 172         ipdata = &ip->chain->data->ipdata;
 173
 174         for (;;) {
 175                 /*
 176                  * Attempt to reuse an existing vnode assignment.  It is
 177                  * possible to race a reclaim so the vget() may fail.  The
 178                  * inode must be unlocked during the vget() to avoid a
 179                  * deadlock against a reclaim.
 180                  */
 181                 vp = ip->vp;
 182                 if (vp) {
 183                         /*
 184                          * Inode must be unlocked during the vget() to avoid
 185                          * possible deadlocks, but leave the ip ref intact.
 186                          *
 187                          * vnode is held to prevent destruction during the
 188                          * vget().  The vget() can still fail if we lost
 189                          * a reclaim race on the vnode.
 190                          */
 191                         vhold_interlocked(vp);
 192                         ostate = hammer2_inode_lock_temp_release(ip);
 193                         if (vget(vp, LK_EXCLUSIVE)) {
 194                                 vdrop(vp);
 195                                 hammer2_inode_lock_temp_restore(ip, ostate);
 196                                 continue;
 197                         }
 198                         hammer2_inode_lock_temp_restore(ip, ostate);
 199                         vdrop(vp);
 200                         /* vp still locked and ref from vget */
 201                         if (ip->vp != vp) {
 202                                 kprintf("hammer2: igetv race %p/%p\n",
 203                                         ip->vp, vp);
 204                                 vput(vp);
 205                                 continue;
 206                         }
 207                         *errorp = 0;
 208                         break;
 209                 }
 210
 211                 /*
 212                  * No vnode exists, allocate a new vnode.  Beware of
 213                  * allocation races.  This function will return an
 214                  * exclusively locked and referenced vnode.
 215                  */
 216                 *errorp = getnewvnode(VT_HAMMER2, pmp->mp, &vp, 0, 0);
 217                 if (*errorp) {
 218                         kprintf("hammer2: igetv getnewvnode failed %d\n",
 219                                 *errorp);
 220                         vp = NULL;
 221                         break;
 222                 }
 223
 224                 /*
 225                  * Lock the inode and check for an allocation race.
 226                  */
 227                 ostate = hammer2_inode_lock_upgrade(ip);
 228                 if (ip->vp != NULL) {
 229                         vp->v_type = VBAD;
 230                         vx_put(vp);
 231                         hammer2_inode_lock_downgrade(ip, ostate);
 232                         continue;
 233                 }
 234
 235                 switch (ipdata->type) {
 236                 case HAMMER2_OBJTYPE_DIRECTORY:
 237                         vp->v_type = VDIR;
 238                         break;
 239                 case HAMMER2_OBJTYPE_REGFILE:
 240                         vp->v_type = VREG;
 241                         vinitvmio(vp, ipdata->size,
 242                                   HAMMER2_LBUFSIZE,
 243                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 244                         break;
 245                 case HAMMER2_OBJTYPE_SOFTLINK:
 246                         /*
 247                          * XXX for now we are using the generic file_read
 248                          * and file_write code so we need a buffer cache
 249                          * association.
 250                          */
 251                         vp->v_type = VLNK;
 252                         vinitvmio(vp, ipdata->size,
 253                                   HAMMER2_LBUFSIZE,
 254                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 255                         break;
 256                 /* XXX FIFO */
 257                 default:
 258                         panic("hammer2: unhandled objtype %d", ipdata->type);
 259                         break;
 260                 }
 261
 262                 if (ip == pmp->iroot)
 263                         vsetflags(vp, VROOT);
 264
 265                 vp->v_data = ip;
 266                 ip->vp = vp;
 267                 hammer2_inode_ref(ip);          /* vp association */
 268                 hammer2_inode_lock_downgrade(ip, ostate);
 269                 break;
 270         }
 271
 272         /*
 273          * Return non-NULL vp and *errorp == 0, or NULL vp and *errorp != 0.
 274          */
 275         if (hammer2_debug & 0x0002) {
 276                 kprintf("igetv vp %p refs %d aux %d\n",
 277                         vp, vp->v_sysref.refcnt, vp->v_auxrefs);
 278         }
 279         return (vp);
 280 }
 281
 282 /*
 283  * The passed-in chain must be locked and the returned inode will also be
 284  * locked.  A ref is added to both the chain and the inode.  The chain lock
 285  * is inherited by the inode structure and should not be separately released.
 286  *
 287  * The hammer2_inode structure regulates the interface between the high level
 288  * kernel VNOPS API and the filesystem backend (the chains).
 289  *
 290  * WARNING!  This routine sucks up the chain's lock (makes it part of the
 291  *           inode lock from the point of view of the inode lock API),
 292  *           so callers need to be careful.
 293  *
 294  * WARNING!  The mount code is allowed to pass dip == NULL for iroot and
 295  *           is allowed to pass pmp == NULL and dip == NULL for sroot.
 296  */
 297 hammer2_inode_t *
 298 hammer2_inode_get(hammer2_mount_t *hmp, hammer2_pfsmount_t *pmp,
 299                   hammer2_inode_t *dip, hammer2_chain_t *chain)
 300 {
 301         hammer2_inode_t *nip;
 302         hammer2_chain_t *ochain;
 303
 304         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
 305
 306         /*
 307          * Interlocked lookup/ref of the inode.  This code is only needed
 308          * when looking up inodes with nlinks != 0 (TODO: optimize out
 309          * otherwise and test for duplicates).
 310          */
 311 again:
 312         for (;;) {
 313                 nip = hammer2_inode_lookup(pmp, chain->data->ipdata.inum);
 314                 if (nip == NULL)
 315                         break;
 316                 ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 317                 if ((nip->flags & HAMMER2_INODE_ONRBTREE) == 0) {
 318                         ccms_thread_unlock(&nip->topo_cst);
 319                         hammer2_inode_drop(nip);
 320                         continue;
 321                 }
 322                 if (nip->chain != chain) {
 323                         hammer2_chain_ref(chain);       /* new nip->chain */
 324                         ochain = nip->chain;
 325                         nip->chain = chain;             /* fully locked   */
 326                         hammer2_chain_drop(ochain);     /* old nip->chain */
 327                 }
 328                 /*
 329                  * Consolidated nip/nip->chain is locked (chain locked
 330                  * by caller).
 331                  */
 332                 return nip;
 333         }
 334
 335         /*
 336          * We couldn't find the inode number, create a new inode.
 337          */
 338         nip = kmalloc(sizeof(*nip), hmp->minode, M_WAITOK | M_ZERO);
 339         nip->inum = chain->data->ipdata.inum;
 340         nip->chain = chain;
 341         hammer2_chain_ref(chain);               /* nip->chain */
 342         nip->pip = dip;                         /* can be NULL */
 343         if (dip)
 344                 hammer2_inode_ref(dip); /* ref dip for nip->pip */
 345
 346         nip->pmp = pmp;
 347         nip->hmp = hmp;
 348
 349         /*
 350          * ref and lock on nip gives it state compatible to after a
 351          * hammer2_inode_lock_ex() call.
 352          */
 353         nip->refs = 1;
 354         ccms_cst_init(&nip->topo_cst, &nip->chain);
 355         ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 356         /* combination of thread lock and chain lock == inode lock */
 357
 358         /*
 359          * Attempt to add the inode.  If it fails we raced another inode
 360          * get.  Undo all the work and try again.
 361          */
 362         if (pmp) {
 363                 spin_lock(&pmp->inum_spin);
 364                 if (RB_INSERT(hammer2_inode_tree, &pmp->inum_tree, nip)) {
 365                         spin_unlock(&pmp->inum_spin);
 366                         ccms_thread_unlock(&nip->topo_cst);
 367                         hammer2_inode_drop(nip);
 368                         goto again;
 369                 }
 370                 atomic_set_int(&nip->flags, HAMMER2_INODE_ONRBTREE);
 371                 spin_unlock(&pmp->inum_spin);
 372         }
 373
 374         return (nip);
 375 }
 376
 377 /*
 378  * Put away an inode, unlocking it and disconnecting it from its chain.
 379  *
 380  * The inode must be exclusively locked on call and non-recursed, with
 381  * at least 2 refs (one belonging to the exclusive lock, and one additional
 382  * ref belonging to the caller).
 383  *
 384  * Upon return the inode typically has one ref remaining which the caller
 385  * drops.
 386  */
 387 void
 388 hammer2_inode_put(hammer2_inode_t *ip)
 389 {
 390         hammer2_inode_t *pip;
 391         hammer2_chain_t *chain;
 392
 393         /*
 394          * Disconnect and unlock chain
 395          */
 396         KKASSERT(ip->refs >= 2);
 397         KKASSERT(ip->topo_cst.count == -1);     /* one excl lock allowed */
 398         if ((chain = ip->chain) != NULL) {
 399                 ip->chain = NULL;
 400                 hammer2_inode_unlock_ex(ip);
 401                 hammer2_chain_unlock(chain);    /* because ip->chain now NULL */
 402                 hammer2_chain_drop(chain);      /* from *_get() */
 403         }
 404
 405         /*
 406          * Disconnect pip
 407          */
 408         if ((pip = ip->pip) != NULL) {
 409                 ip->pip = NULL;
 410                 hammer2_inode_drop(pip);
 411         }
 412 }
 413
 414 /*
 415  * Create a new inode in the specified directory using the vattr to
 416  * figure out the type of inode.
 417  *
 418  * If no error occurs the new inode with its chain locked is returned in
 419  * *nipp, otherwise an error is returned and *nipp is set to NULL.
 420  *
 421  * If vap and/or cred are NULL the related fields are not set and the
 422  * inode type defaults to a directory.  This is used when creating PFSs
 423  * under the super-root, so the inode number is set to 1 in this case.
 424  *
 425  * dip is not locked on entry.
 426  */
 427 hammer2_inode_t *
 428 hammer2_inode_create(hammer2_trans_t *trans, hammer2_inode_t *dip,
 429                      struct vattr *vap, struct ucred *cred,
 430                      const uint8_t *name, size_t name_len,
 431                      int *errorp)
 432 {
 433         hammer2_inode_data_t *dipdata;
 434         hammer2_inode_data_t *nipdata;
 435         hammer2_mount_t *hmp;
 436         hammer2_chain_t *chain;
 437         hammer2_chain_t *parent;
 438         hammer2_inode_t *nip;
 439         hammer2_key_t lhc;
 440         int error;
 441         uid_t xuid;
 442         uuid_t dip_uid;
 443         uuid_t dip_gid;
 444         uint32_t dip_mode;
 445
 446         hmp = dip->hmp;
 447         lhc = hammer2_dirhash(name, name_len);
 448         *errorp = 0;
 449
 450         /*
 451          * Locate the inode or indirect block to create the new
 452          * entry in.  At the same time check for key collisions
 453          * and iterate until we don't get one.
 454          *
 455          * NOTE: hidden inodes do not have iterators.
 456          */
 457 retry:
 458         hammer2_inode_lock_ex(dip);
 459         dipdata = &dip->chain->data->ipdata;
 460         dip_uid = dipdata->uid;
 461         dip_gid = dipdata->gid;
 462         dip_mode = dipdata->mode;
 463
 464         parent = hammer2_chain_lookup_init(dip->chain, 0);
 465         error = 0;
 466         while (error == 0) {
 467                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 468                 if (chain == NULL)
 469                         break;
 470                 if ((lhc & HAMMER2_DIRHASH_VISIBLE) == 0)
 471                         error = ENOSPC;
 472                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 473                         error = ENOSPC;
 474                 hammer2_chain_unlock(chain);
 475                 chain = NULL;
 476                 ++lhc;
 477         }
 478         if (error == 0) {
 479                 error = hammer2_chain_create(trans, &parent, &chain,
 480                                              lhc, 0,
 481                                              HAMMER2_BREF_TYPE_INODE,
 482                                              HAMMER2_INODE_BYTES);
 483         }
 484
 485         /*
 486          * Cleanup and handle retries.
 487          */
 488         if (error == EAGAIN) {
 489                 hammer2_chain_ref(parent);
 490                 hammer2_chain_lookup_done(parent);
 491                 hammer2_inode_unlock_ex(dip);
 492                 hammer2_chain_wait(parent);
 493                 hammer2_chain_drop(parent);
 494                 goto retry;
 495         }
 496         hammer2_chain_lookup_done(parent);
 497         hammer2_inode_unlock_ex(dip);
 498
 499         if (error) {
 500                 KKASSERT(chain == NULL);
 501                 *errorp = error;
 502                 return (NULL);
 503         }
 504
 505         /*
 506          * Set up the new inode.
 507          *
 508          * NOTE: *_get() integrates chain's lock into the inode lock.
 509          *
 510          * NOTE: Only one new inode can currently be created per
 511          *       transaction.  If the need arises we can adjust
 512          *       hammer2_trans_init() to allow more.
 513          */
 514         chain->data->ipdata.inum = trans->sync_tid;
 515         nip = hammer2_inode_get(dip->hmp, dip->pmp, dip, chain);
 516         nipdata = &chain->data->ipdata;
 517
 518         if (vap) {
 519                 KKASSERT(trans->inodes_created == 0);
 520                 nipdata->type = hammer2_get_obj_type(vap->va_type);
 521                 nipdata->inum = trans->sync_tid;
 522                 ++trans->inodes_created;
 523         } else {
 524                 nipdata->type = HAMMER2_OBJTYPE_DIRECTORY;
 525                 nipdata->inum = 1;
 526         }
 527         nipdata->version = HAMMER2_INODE_VERSION_ONE;
 528         hammer2_update_time(&nipdata->ctime);
 529         nipdata->mtime = nipdata->ctime;
 530         if (vap)
 531                 nipdata->mode = vap->va_mode;
 532         nipdata->nlinks = 1;
 533         if (vap) {
 534                 if (dip) {
 535                         xuid = hammer2_to_unix_xid(&dip_uid);
 536                         xuid = vop_helper_create_uid(dip->pmp->mp,
 537                                                      dip_mode,
 538                                                      xuid,
 539                                                      cred,
 540                                                      &vap->va_mode);
 541                 } else {
 542                         xuid = 0;
 543                 }
 544                 if (vap->va_vaflags & VA_UID_UUID_VALID)
 545                         nipdata->uid = vap->va_uid_uuid;
 546                 else if (vap->va_uid != (uid_t)VNOVAL)
 547                         hammer2_guid_to_uuid(&nipdata->uid, vap->va_uid);
 548                 else
 549                         hammer2_guid_to_uuid(&nipdata->uid, xuid);
 550
 551                 if (vap->va_vaflags & VA_GID_UUID_VALID)
 552                         nipdata->gid = vap->va_gid_uuid;
 553                 else if (vap->va_gid != (gid_t)VNOVAL)
 554                         hammer2_guid_to_uuid(&nipdata->gid, vap->va_gid);
 555                 else if (dip)
 556                         nipdata->gid = dip_gid;
 557         }
 558
 559         /*
 560          * Regular files and softlinks allow a small amount of data to be
 561          * directly embedded in the inode.  This flag will be cleared if
 562          * the size is extended past the embedded limit.
 563          */
 564         if (nipdata->type == HAMMER2_OBJTYPE_REGFILE ||
 565             nipdata->type == HAMMER2_OBJTYPE_SOFTLINK) {
 566                 nipdata->op_flags |= HAMMER2_OPFLAG_DIRECTDATA;
 567         }
 568
 569         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 570         bcopy(name, nipdata->filename, name_len);
 571         nipdata->name_key = lhc;
 572         nipdata->name_len = name_len;
 573
 574         return (nip);
 575 }
 576
 577 /*
 578  * chain may have been moved around by the create.
 579  */
 580 static
 581 void
 582 hammer2_chain_refactor(hammer2_chain_t **chainp)
 583 {
 584         hammer2_chain_t *chain = *chainp;
 585         hammer2_chain_t *tmp;
 586
 587         while (chain->duplink && (chain->flags & HAMMER2_CHAIN_DELETED)) {
 588                 tmp = chain->duplink;
 589                 while (tmp->duplink && (tmp->flags & HAMMER2_CHAIN_DELETED))
 590                         tmp = tmp->duplink;
 591                 hammer2_chain_ref(chain);
 592                 hammer2_chain_unlock(chain);
 593                 hammer2_chain_lock(tmp, HAMMER2_RESOLVE_ALWAYS);
 594                 hammer2_chain_drop(chain);
 595                 chain = tmp;
 596                 *chainp = chain;
 597         }
 598 }
 599
 600
 601 /*
 602  * ochain represents the target file inode.  We need to move it to the
 603  * specified common parent directory (dip) and rename it to a special
 604  * invisible "0xINODENUMBER" filename.
 605  *
 606  * We use chain_duplicate and duplicate ochain at the new location,
 607  * renaming it appropriately.  We create a temporary chain and
 608  * then delete it to placemark where the duplicate will go.  Both of
 609  * these use the inode number for (lhc) (the key), generating the
 610  * invisible filename.
 611  */
 612 static
 613 hammer2_chain_t *
 614 hammer2_hardlink_shiftup(hammer2_trans_t *trans, hammer2_chain_t **ochainp,
 615                         hammer2_inode_t *dip, int *errorp)
 616 {
 617         hammer2_inode_data_t *nipdata;
 618         hammer2_mount_t *hmp;
 619         hammer2_chain_t *parent;
 620         hammer2_chain_t *ochain;
 621         hammer2_chain_t *nchain;
 622         hammer2_chain_t *tmp;
 623         hammer2_key_t lhc;
 624         hammer2_blockref_t bref;
 625
 626         ochain = *ochainp;
 627         *errorp = 0;
 628         hmp = dip->hmp;
 629         lhc = ochain->data->ipdata.inum;
 630         KKASSERT((lhc & HAMMER2_DIRHASH_VISIBLE) == 0);
 631
 632         /*
 633          * Locate the inode or indirect block to create the new
 634          * entry in.  lhc represents the inode number so there is
 635          * no collision iteration.
 636          *
 637          * There should be no key collisions with invisible inode keys.
 638          */
 639 retry:
 640         parent = hammer2_chain_lookup_init(dip->chain, 0);
 641         nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 642         if (nchain) {
 643                 kprintf("X3 chain %p parent %p dip %p dip->chain %p\n",
 644                         nchain, parent, dip, dip->chain);
 645                 hammer2_chain_unlock(nchain);
 646                 nchain = NULL;
 647                 *errorp = ENOSPC;
 648 #if 0
 649                 Debugger("X3");
 650 #endif
 651         }
 652
 653         /*
 654          * Create entry in common parent directory using the seek position
 655          * calculated above.
 656          */
 657         if (*errorp == 0) {
 658                 KKASSERT(nchain == NULL);
 659                 *errorp = hammer2_chain_create(trans, &parent, &nchain,
 660                                                lhc, 0,
 661                                                HAMMER2_BREF_TYPE_INODE,/* n/a */
 662                                                HAMMER2_INODE_BYTES);   /* n/a */
 663                 hammer2_chain_refactor(&ochain);
 664                 *ochainp = ochain;
 665         }
 666
 667         /*
 668          * Cleanup and handle retries.
 669          */
 670         if (*errorp == EAGAIN) {
 671                 hammer2_chain_ref(parent);
 672                 hammer2_chain_lookup_done(parent);
 673                 hammer2_chain_wait(parent);
 674                 hammer2_chain_drop(parent);
 675                 goto retry;
 676         }
 677
 678         /*
 679          * Handle the error case
 680          */
 681         if (*errorp) {
 682                 KKASSERT(nchain == NULL);
 683                 hammer2_chain_lookup_done(parent);
 684                 return (NULL);
 685         }
 686
 687         /*
 688          * Use chain as a placeholder for (lhc), delete it and replace
 689          * it with our duplication.
 690          *
 691          * Gain a second lock on ochain for the duplication function to
 692          * unlock, maintain the caller's original lock across the call.
 693          *
 694          * This is a bit messy.
 695          */
 696         hammer2_chain_delete(trans, parent, nchain);
 697         hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
 698         tmp = ochain;
 699         bref = tmp->bref;
 700         bref.key = lhc;                 /* invisible dir entry key */
 701         bref.keybits = 0;
 702         hammer2_chain_duplicate(trans, parent, nchain->index, &tmp, &bref);
 703         hammer2_chain_lookup_done(parent);
 704         hammer2_chain_unlock(nchain);   /* no longer needed */
 705
 706         /*
 707          * Now set chain to our duplicate and modify it appropriately.
 708          *
 709          * Directory entries are inodes but this is a hidden hardlink
 710          * target.  The name isn't used but to ease debugging give it
 711          * a name after its inode number.
 712          */
 713         nchain = tmp;
 714         tmp = NULL;     /* safety */
 715
 716         hammer2_chain_modify(trans, &nchain, HAMMER2_MODIFY_ASSERTNOCOPY);
 717         nipdata = &nchain->data->ipdata;
 718         ksnprintf(nipdata->filename, sizeof(nipdata->filename),
 719                   "0x%016jx", (intmax_t)nipdata->inum);
 720         nipdata->name_len = strlen(nipdata->filename);
 721         nipdata->name_key = lhc;
 722
 723         return (nchain);
 724 }
 725
 726 /*
 727  * Connect the target inode represented by (*chainp) to the media topology
 728  * at (dip, name, len).
 729  *
 730  * If hlink is TRUE this function creates an OBJTYPE_HARDLINK directory
 731  * entry instead of connecting (*chainp).
 732  *
 733  * If hlink is FALSE this function uses chain_duplicate() to make a copy
 734  * if (*chainp) in the directory entry.  (*chainp) is likely to be deleted
 735  * by the caller in this case (e.g. rename).
 736  */
 737 int
 738 hammer2_inode_connect(hammer2_trans_t *trans, int hlink,
 739                       hammer2_inode_t *dip, hammer2_chain_t **chainp,
 740                       const uint8_t *name, size_t name_len)
 741 {
 742         hammer2_inode_data_t *ipdata;
 743         hammer2_mount_t *hmp;
 744         hammer2_chain_t *nchain;
 745         hammer2_chain_t *parent;
 746         hammer2_chain_t *ochain;
 747         hammer2_key_t lhc;
 748         int error;
 749
 750         hmp = dip->hmp;
 751
 752         ochain = *chainp;
 753
 754         /*
 755          * Since ochain is either disconnected from the topology or represents
 756          * a hardlink terminus which is always a parent of or equal to dip,
 757          * we should be able to safely lock dip->chain for our setup.
 758          */
 759         parent = hammer2_chain_lookup_init(dip->chain, 0);
 760
 761         lhc = hammer2_dirhash(name, name_len);
 762
 763         /*
 764          * Locate the inode or indirect block to create the new
 765          * entry in.  At the same time check for key collisions
 766          * and iterate until we don't get one.
 767          */
 768         error = 0;
 769         while (error == 0) {
 770                 nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 771                 if (nchain == NULL)
 772                         break;
 773                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 774                         error = ENOSPC;
 775                 hammer2_chain_unlock(nchain);
 776                 nchain = NULL;
 777                 ++lhc;
 778         }
 779
 780         if (error == 0) {
 781                 if (hlink) {
 782                         /*
 783                          * Hardlink pointer needed, create totally fresh
 784                          * directory entry.
 785                          */
 786                         KKASSERT(nchain == NULL);
 787                         error = hammer2_chain_create(trans, &parent, &nchain,
 788                                                      lhc, 0,
 789                                                      HAMMER2_BREF_TYPE_INODE,
 790                                                      HAMMER2_INODE_BYTES);
 791                         hammer2_chain_refactor(&ochain);
 792                 } else {
 793                         /*
 794                          * Reconnect the original chain and rename.  Use
 795                          * chain_duplicate().  The caller will likely delete
 796                          * or has already deleted the original chain in
 797                          * this case.
 798                          */
 799                         nchain = ochain;
 800                         ochain = NULL;
 801                         hammer2_chain_duplicate(trans, NULL, -1, &nchain, NULL);
 802                         error = hammer2_chain_create(trans, &parent, &nchain,
 803                                                      lhc, 0,
 804                                                      HAMMER2_BREF_TYPE_INODE,
 805                                                      HAMMER2_INODE_BYTES);
 806                 }
 807         }
 808
 809         /*
 810          * Unlock stuff.
 811          */
 812         KKASSERT(error != EAGAIN);
 813         hammer2_chain_lookup_done(parent);
 814         parent = NULL;
 815
 816         /*
 817          * nchain should be NULL on error, leave ochain (== *chainp) alone.
 818          */
 819         if (error) {
 820                 KKASSERT(nchain == NULL);
 821                 return (error);
 822         }
 823
 824         /*
 825          * Directory entries are inodes so if the name has changed we have
 826          * to update the inode.
 827          *
 828          * When creating an OBJTYPE_HARDLINK entry remember to unlock the
 829          * chain, the caller will access the hardlink via the actual hardlink
 830          * target file and not the hardlink pointer entry, so we must still
 831          * return ochain.
 832          */
 833         if (hlink && hammer2_hardlink_enable >= 0) {
 834                 /*
 835                  * Create the HARDLINK pointer.  oip represents the hardlink
 836                  * target in this situation.
 837                  *
 838                  * We will return ochain (the hardlink target).
 839                  */
 840                 hammer2_chain_modify(trans, &nchain,
 841                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 842                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 843                 ipdata = &nchain->data->ipdata;
 844                 bcopy(name, ipdata->filename, name_len);
 845                 ipdata->name_key = lhc;
 846                 ipdata->name_len = name_len;
 847                 ipdata->target_type = ochain->data->ipdata.type;
 848                 ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
 849                 ipdata->inum = ochain->data->ipdata.inum;
 850                 ipdata->nlinks = 1;
 851                 hammer2_chain_unlock(nchain);
 852                 nchain = ochain;
 853                 ochain = NULL;
 854         } else if (hlink && hammer2_hardlink_enable < 0) {
 855                 /*
 856                  * Create a snapshot (hardlink fake mode for debugging).
 857                  * (ochain already flushed above so we can just copy the
 858                  * bref XXX).
 859                  *
 860                  * Since this is a snapshot we return nchain in the fake
 861                  * hardlink case.
 862                  */
 863                 hammer2_chain_modify(trans, &nchain,
 864                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 865                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 866                 ipdata = &nchain->data->ipdata;
 867                 *ipdata = ochain->data->ipdata;
 868                 bcopy(name, ipdata->filename, name_len);
 869                 ipdata->name_key = lhc;
 870                 ipdata->name_len = name_len;
 871                 kprintf("created fake hardlink %*.*s\n",
 872                         (int)name_len, (int)name_len, name);
 873         } else {
 874                 /*
 875                  * nchain is a duplicate of ochain at the new location.
 876                  * We must fixup the name stored in oip.  The bref key
 877                  * has already been set up.
 878                  */
 879                 hammer2_chain_modify(trans, &nchain,
 880                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 881                 ipdata = &nchain->data->ipdata;
 882
 883                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 884                 bcopy(name, ipdata->filename, name_len);
 885                 ipdata->name_key = lhc;
 886                 ipdata->name_len = name_len;
 887                 ipdata->nlinks = 1;
 888         }
 889
 890         /*
 891          * We are replacing ochain with nchain, unlock ochain.  In the
 892          * case where ochain is left unchanged the code above sets
 893          * nchain to ochain and ochain to NULL, resulting in a NOP here.
 894          */
 895         if (ochain)
 896                 hammer2_chain_unlock(ochain);
 897         *chainp = nchain;
 898
 899         return (0);
 900 }
 901
 902 /*
 903  * Caller must hold exactly ONE exclusive lock on the inode.  *nchainp
 904  * must be exclusive locked (its own exclusive lock even if it is the
 905  * same as ip->chain).
 906  *
 907  * This function replaces ip->chain.  The exclusive lock on the passed
 908  * nchain is inherited by the inode and the caller becomes responsible
 909  * for unlocking it when the caller unlocks the inode.
 910  *
 911  * ochain was locked by the caller indirectly via the inode lock.  Since
 912  * ip->chain is being repointed, we become responsible for cleaning up
 913  * that lock.
 914  *
 915  * Return *nchainp = NULL as a safety.
 916  */
 917 void
 918 hammer2_inode_repoint(hammer2_inode_t *ip, hammer2_inode_t *pip,
 919                       hammer2_chain_t *nchain)
 920 {
 921         hammer2_chain_t *ochain;
 922         hammer2_inode_t *opip;
 923
 924         /*
 925          * ip->chain points to the hardlink target, not the hardlink psuedo
 926          * inode.  Do not repoint nchain to the pseudo-node.
 927          */
 928         if (nchain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK)
 929                 return;
 930
 931         /*
 932          * Repoint ip->chain if necessary.
 933          *
 934          * (Inode must be locked exclusively by parent)
 935          */
 936         ochain = ip->chain;
 937         if (ochain != nchain) {
 938                 hammer2_chain_ref(nchain);              /* for ip->chain */
 939                 ip->chain = nchain;
 940                 if (ochain) {
 941                         hammer2_chain_unlock(ochain);
 942                         hammer2_chain_drop(ochain);     /* for ip->chain */
 943                 }
 944                 /* replace locked chain in ip (additional lock) */
 945                 hammer2_chain_lock(nchain, HAMMER2_RESOLVE_ALWAYS);
 946         }
 947         if (ip->pip != pip) {
 948                 opip = ip->pip;
 949                 if (pip)
 950                         hammer2_inode_ref(pip);
 951                 ip->pip = pip;
 952                 if (opip)
 953                         hammer2_inode_drop(opip);
 954         }
 955 }
 956
 957 /*
 958  * Unlink the file from the specified directory inode.  The directory inode
 959  * does not need to be locked.  The caller should pass a non-NULL (ip)
 960  * representing the object being removed only if the related vnode is
 961  * potentially inactive (not referenced in the caller's active path),
 962  * so we can vref/vrele it to trigger the VOP_INACTIVE path and properly
 963  * recycle it.
 964  *
 965  * isdir determines whether a directory/non-directory check should be made.
 966  * No check is made if isdir is set to -1.
 967  *
 968  * NOTE!  This function does not prevent the underlying file from still
 969  *        being used if it has other refs (such as from an inode, or if it's
 970  *        chain is manually held).  However, the caller is responsible for
 971  *        fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()).
 972  */
 973 int
 974 hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
 975                     const uint8_t *name, size_t name_len,
 976                     int isdir, int *hlinkp)
 977 {
 978         hammer2_inode_data_t *ipdata;
 979         hammer2_mount_t *hmp;
 980         hammer2_chain_t *parent;
 981         hammer2_chain_t *ochain;
 982         hammer2_chain_t *chain;
 983         hammer2_chain_t *dparent;
 984         hammer2_chain_t *dchain;
 985         hammer2_key_t lhc;
 986         int error;
 987         int parent_ref;
 988         uint8_t type;
 989
 990         parent_ref = 0;
 991         error = 0;
 992         ochain = NULL;
 993         hmp = dip->hmp;
 994         lhc = hammer2_dirhash(name, name_len);
 995
 996         /*
 997          * Search for the filename in the directory
 998          */
 999         if (hlinkp)
1000                 *hlinkp = 0;
1001         hammer2_inode_lock_ex(dip);
1002
1003         parent = hammer2_chain_lookup_init(dip->chain, 0);
1004         chain = hammer2_chain_lookup(&parent,
1005                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1006                                      0);
1007         while (chain) {
1008                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1009                     name_len == chain->data->ipdata.name_len &&
1010                     bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
1011                         break;
1012                 }
1013                 chain = hammer2_chain_next(&parent, chain,
1014                                            lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1015                                            0);
1016         }
1017         hammer2_inode_unlock_ex(dip);   /* retain parent */
1018
1019         /*
1020          * Not found or wrong type (isdir < 0 disables the type check).
1021          * If a hardlink pointer, type checks use the hardlink target.
1022          */
1023         if (chain == NULL) {
1024                 error = ENOENT;
1025                 goto done;
1026         }
1027         if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) {
1028                 if (hlinkp)
1029                         *hlinkp = 1;
1030                 type = chain->data->ipdata.target_type;
1031         }
1032
1033         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
1034                 error = ENOTDIR;
1035                 goto done;
1036         }
1037         if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) {
1038                 error = EISDIR;
1039                 goto done;
1040         }
1041
1042         /*
1043          * Hardlink must be resolved.  We can't hold parent locked while we
1044          * do this or we could deadlock.
1045          *
1046          * On success chain will be adjusted to point at the hardlink target
1047          * and ochain will point to the hardlink pointer in the original
1048          * directory.  Otherwise chain remains pointing to the original.
1049          */
1050         if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
1051                 KKASSERT(parent_ref == 0);
1052                 hammer2_chain_unlock(parent);
1053                 parent = NULL;
1054                 error = hammer2_hardlink_find(dip, &chain, &ochain);
1055         }
1056
1057         /*
1058          * If this is a directory the directory must be empty.  However, if
1059          * isdir < 0 we are doing a rename and the directory does not have
1060          * to be empty, and if isdir > 1 we are deleting a PFS/snapshot
1061          * and the directory does not have to be empty.
1062          *
1063          * NOTE: We check the full key range here which covers both visible
1064          *       and invisible entries.  Theoretically there should be no
1065          *       invisible (hardlink target) entries if there are no visible
1066          *       entries.
1067          */
1068         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
1069                 dparent = hammer2_chain_lookup_init(chain, 0);
1070                 dchain = hammer2_chain_lookup(&dparent,
1071                                               0, (hammer2_key_t)-1,
1072                                               HAMMER2_LOOKUP_NODATA);
1073                 if (dchain) {
1074                         hammer2_chain_unlock(dchain);
1075                         hammer2_chain_lookup_done(dparent);
1076                         error = ENOTEMPTY;
1077                         goto done;
1078                 }
1079                 hammer2_chain_lookup_done(dparent);
1080                 dparent = NULL;
1081                 /* dchain NULL */
1082         }
1083
1084         /*
1085          * Ok, we can now unlink the chain.  We always decrement nlinks even
1086          * if the entry can be deleted in case someone has the file open and
1087          * does an fstat().
1088          *
1089          * The chain itself will no longer be in the on-media topology but
1090          * can still be flushed to the media (e.g. if an open descriptor
1091          * remains).  When the last vnode/ip ref goes away the chain will
1092          * be marked unmodified, avoiding any further (now unnecesary) I/O.
1093          *
1094          * A non-NULL ochain indicates a hardlink.
1095          */
1096         if (ochain) {
1097                 /*
1098                  * Delete the original hardlink pointer.
1099                  *
1100                  * NOTE: parent from above is NULL when ochain != NULL
1101                  *       so we can reuse it.
1102                  */
1103                 hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
1104                 parent_ref = 1;
1105                 for (;;) {
1106                         parent = ochain->parent;
1107                         hammer2_chain_ref(parent);
1108                         hammer2_chain_unlock(ochain);
1109                         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1110                         hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
1111                         if (ochain->parent == parent)
1112                                 break;
1113                         hammer2_chain_unlock(parent);
1114                         hammer2_chain_drop(parent);
1115                 }
1116
1117                 hammer2_chain_delete(trans, parent, ochain);
1118                 hammer2_chain_unlock(ochain);
1119                 hammer2_chain_unlock(parent);
1120                 hammer2_chain_drop(parent);
1121                 parent = NULL;
1122
1123                 /*
1124                  * Then decrement nlinks on hardlink target, deleting
1125                  * the target when nlinks drops to 0.
1126                  */
1127                 if (chain->data->ipdata.nlinks == 1) {
1128                         dparent = chain->parent;
1129                         hammer2_chain_ref(chain);
1130                         hammer2_chain_unlock(chain);
1131                         hammer2_chain_lock(dparent, HAMMER2_RESOLVE_ALWAYS);
1132                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
1133                         hammer2_chain_drop(chain);
1134                         hammer2_chain_modify(trans, &chain, 0);
1135                         --chain->data->ipdata.nlinks;
1136                         hammer2_chain_delete(trans, dparent, chain);
1137                         hammer2_chain_unlock(dparent);
1138                 } else {
1139                         hammer2_chain_modify(trans, &chain, 0);
1140                         --chain->data->ipdata.nlinks;
1141                 }
1142         } else {
1143                 /*
1144                  * Otherwise this was not a hardlink and we can just
1145                  * remove the entry and decrement nlinks.
1146                  *
1147                  * NOTE: *_get() integrates chain's lock into the inode lock.
1148                  */
1149                 hammer2_chain_modify(trans, &chain, 0);
1150                 ipdata = &chain->data->ipdata;
1151                 --ipdata->nlinks;
1152                 hammer2_chain_delete(trans, parent, chain);
1153         }
1154
1155         error = 0;
1156 done:
1157         if (chain)
1158                 hammer2_chain_unlock(chain);
1159         if (parent) {
1160                 hammer2_chain_lookup_done(parent);
1161                 if (parent_ref)
1162                         hammer2_chain_drop(parent);
1163         }
1164         if (ochain)
1165                 hammer2_chain_drop(ochain);
1166
1167         return error;
1168 }
1169
1170 /*
1171  * Calculate the allocation size for the file fragment straddling EOF
1172  */
1173 int
1174 hammer2_inode_calc_alloc(hammer2_key_t filesize)
1175 {
1176         int frag = (int)filesize & HAMMER2_PBUFMASK;
1177         int radix;
1178
1179         if (frag == 0)
1180                 return(0);
1181         for (radix = HAMMER2_MINALLOCRADIX; frag > (1 << radix); ++radix)
1182                 ;
1183         return (radix);
1184 }
1185
1186 /*
1187  * Given an exclusively locked inode we consolidate its chain for hardlink
1188  * creation, adding (nlinks) to the file's link count and potentially
1189  * relocating the inode to a directory common to ip->pip and tdip.
1190  *
1191  * Returns a locked chain in (*chainp) (the chain's lock is in addition to
1192  * any lock it might already have due to the inode being locked).  *chainp
1193  * is set unconditionally and its previous contents can be garbage.
1194  *
1195  * The caller is responsible for replacing ip->chain, not us.  For certain
1196  * operations such as renames the caller may do additional manipulation
1197  * of the chain before replacing ip->chain.
1198  */
1199 int
1200 hammer2_hardlink_consolidate(hammer2_trans_t *trans, hammer2_inode_t *ip,
1201                              hammer2_chain_t **chainp,
1202                              hammer2_inode_t *tdip, int nlinks)
1203 {
1204         hammer2_inode_data_t *ipdata;
1205         hammer2_mount_t *hmp;
1206         hammer2_inode_t *fdip;
1207         hammer2_inode_t *cdip;
1208         hammer2_chain_t *chain;
1209         hammer2_chain_t *nchain;
1210         hammer2_chain_t *parent;
1211         int error;
1212
1213         /*
1214          * Extra lock on chain so it can be returned locked.
1215          */
1216         hmp = tdip->hmp;
1217
1218         chain = ip->chain;
1219         error = hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
1220         KKASSERT(error == 0);
1221
1222         if (nlinks == 0 &&                      /* no hardlink needed */
1223             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE)) {
1224                 *chainp = chain;
1225                 return (0);
1226         }
1227         if (hammer2_hardlink_enable < 0) {      /* fake hardlinks */
1228                 *chainp = chain;
1229                 return (0);
1230         }
1231
1232         if (hammer2_hardlink_enable == 0) {     /* disallow hardlinks */
1233                 hammer2_chain_unlock(chain);
1234                 *chainp = NULL;
1235                 return (ENOTSUP);
1236         }
1237
1238         /*
1239          * cdip will be returned with a ref, but not locked.
1240          */
1241         fdip = ip->pip;
1242         cdip = hammer2_inode_common_parent(fdip, tdip);
1243
1244         /*
1245          * If no change in the hardlink's target directory is required and
1246          * this is already a hardlink target, all we need to do is adjust
1247          * the link count.
1248          *
1249          * XXX The common parent is a big wiggly due to duplication from
1250          *     renames.  Compare the core (RBTREE) pointer instead of the
1251          *     ip's.
1252          */
1253         if (cdip == fdip &&
1254             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1255                 if (nlinks) {
1256                         hammer2_chain_modify(trans, &chain, 0);
1257                         chain->data->ipdata.nlinks += nlinks;
1258                 }
1259                 *chainp = chain;
1260                 error = 0;
1261                 goto done;
1262         }
1263
1264         /*
1265          * We either have to move an existing hardlink target or we have
1266          * to create a fresh hardlink target.
1267          *
1268          * Hardlink targets are hidden inodes in a parent directory common
1269          * to all directory entries referencing the hardlink.
1270          */
1271         nchain = hammer2_hardlink_shiftup(trans, &chain, cdip, &error);
1272
1273         if (error == 0) {
1274                 /*
1275                  * Bump nlinks on duplicated hidden inode, repoint
1276                  * ip->chain.
1277                  */
1278                 hammer2_chain_modify(trans, &nchain, 0);
1279                 nchain->data->ipdata.nlinks += nlinks;
1280                 hammer2_inode_repoint(ip, cdip, nchain);
1281
1282                 /*
1283                  * If the old chain is not a hardlink target then replace
1284                  * it with a OBJTYPE_HARDLINK pointer.
1285                  *
1286                  * If the old chain IS a hardlink target then delete it.
1287                  */
1288                 if (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) {
1289                         /*
1290                          * Replace original non-hardlink that's been dup'd
1291                          * with a special hardlink directory entry.  We must
1292                          * set the DIRECTDATA flag to prevent sub-chains
1293                          * from trying to synchronize to the inode if the
1294                          * file is extended afterwords.
1295                          */
1296                         hammer2_chain_modify(trans, &chain, 0);
1297                         ipdata = &chain->data->ipdata;
1298                         ipdata->target_type = ipdata->type;
1299                         ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
1300                         ipdata->uflags = 0;
1301                         ipdata->rmajor = 0;
1302                         ipdata->rminor = 0;
1303                         ipdata->ctime = 0;
1304                         ipdata->mtime = 0;
1305                         ipdata->atime = 0;
1306                         ipdata->btime = 0;
1307                         bzero(&ipdata->uid, sizeof(ipdata->uid));
1308                         bzero(&ipdata->gid, sizeof(ipdata->gid));
1309                         ipdata->op_flags = HAMMER2_OPFLAG_DIRECTDATA;
1310                         ipdata->cap_flags = 0;
1311                         ipdata->mode = 0;
1312                         ipdata->size = 0;
1313                         ipdata->nlinks = 1;
1314                         ipdata->iparent = 0;    /* XXX */
1315                         ipdata->pfs_type = 0;
1316                         ipdata->pfs_inum = 0;
1317                         bzero(&ipdata->pfs_clid, sizeof(ipdata->pfs_clid));
1318                         bzero(&ipdata->pfs_fsid, sizeof(ipdata->pfs_fsid));
1319                         ipdata->data_quota = 0;
1320                         ipdata->data_count = 0;
1321                         ipdata->inode_quota = 0;
1322                         ipdata->inode_count = 0;
1323                         ipdata->attr_tid = 0;
1324                         ipdata->dirent_tid = 0;
1325                         bzero(&ipdata->u, sizeof(ipdata->u));
1326                         /* XXX transaction ids */
1327                 } else {
1328                         kprintf("DELETE INVISIBLE\n");
1329                         for (;;) {
1330                                 parent = chain->parent;
1331                                 hammer2_chain_ref(parent);
1332                                 hammer2_chain_ref(chain);
1333                                 hammer2_chain_unlock(chain);
1334                                 hammer2_chain_lock(parent,
1335                                                    HAMMER2_RESOLVE_ALWAYS);
1336                                 hammer2_chain_lock(chain,
1337                                                    HAMMER2_RESOLVE_ALWAYS);
1338                                 hammer2_chain_drop(chain);
1339                                 if (chain->parent == parent)
1340                                         break;
1341                                 hammer2_chain_unlock(parent);
1342                                 hammer2_chain_drop(parent);
1343                         }
1344                         hammer2_chain_delete(trans, parent, chain);
1345                         hammer2_chain_unlock(parent);
1346                         hammer2_chain_drop(parent);
1347                 }
1348
1349                 /*
1350                  * Return the new chain.
1351                  */
1352                 hammer2_chain_unlock(chain);
1353                 *chainp = nchain;
1354         } else {
1355                 /*
1356                  * Return an error
1357                  */
1358                 hammer2_chain_unlock(chain);
1359                 *chainp = NULL;
1360         }
1361
1362         /*
1363          * Cleanup, chain/nchain already dealt with.
1364          */
1365 done:
1366         hammer2_inode_drop(cdip);
1367
1368         return (error);
1369 }
1370
1371 /*
1372  * If (*ochainp) is non-NULL it points to the forward OBJTYPE_HARDLINK
1373  * inode while (*chainp) points to the resolved (hidden hardlink
1374  * target) inode.  In this situation when nlinks is 1 we wish to
1375  * deconsolidate the hardlink, moving it back to the directory that now
1376  * represents the only remaining link.
1377  */
1378 int
1379 hammer2_hardlink_deconsolidate(hammer2_trans_t *trans,
1380                                hammer2_inode_t *dip,
1381                                hammer2_chain_t **chainp,
1382                                hammer2_chain_t **ochainp)
1383 {
1384         if (*ochainp == NULL)
1385                 return (0);
1386         /* XXX */
1387         return (0);
1388 }
1389
1390 /*
1391  * The caller presents a locked *chainp pointing to a HAMMER2_BREF_TYPE_INODE
1392  * with an obj_type of HAMMER2_OBJTYPE_HARDLINK.  This routine will gobble
1393  * the *chainp and return a new locked *chainp representing the file target
1394  * (the original *chainp will be unlocked).
1395  *
1396  * When a match is found the chain representing the original HARDLINK
1397  * will be returned in *ochainp with a ref, but not locked.
1398  *
1399  * When no match is found *chainp is set to NULL and EIO is returned.
1400  * (*ochainp) will still be set to the original chain with a ref but not
1401  * locked.
1402  */
1403 int
1404 hammer2_hardlink_find(hammer2_inode_t *dip, hammer2_chain_t **chainp,
1405                       hammer2_chain_t **ochainp)
1406 {
1407         hammer2_chain_t *chain = *chainp;
1408         hammer2_chain_t *parent;
1409         hammer2_inode_t *ip;
1410         hammer2_inode_t *pip;
1411         hammer2_key_t lhc;
1412
1413         pip = dip;
1414         hammer2_inode_ref(pip);         /* for loop */
1415         hammer2_chain_ref(chain);       /* for (*ochainp) */
1416         *ochainp = chain;
1417
1418         /*
1419          * Locate the hardlink.  pip is referenced and not locked,
1420          * ipp.
1421          *
1422          * chain is reused.
1423          */
1424         lhc = chain->data->ipdata.inum;
1425         hammer2_chain_unlock(chain);
1426         chain = NULL;
1427
1428         while ((ip = pip) != NULL) {
1429                 hammer2_inode_lock_ex(ip);
1430                 parent = hammer2_chain_lookup_init(ip->chain, 0);
1431                 hammer2_inode_drop(ip);                 /* loop */
1432                 KKASSERT(parent->bref.type == HAMMER2_BREF_TYPE_INODE);
1433                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
1434                 hammer2_chain_lookup_done(parent);
1435                 if (chain)
1436                         break;
1437                 pip = ip->pip;          /* safe, ip held locked */
1438                 if (pip)
1439                         hammer2_inode_ref(pip);         /* loop */
1440                 hammer2_inode_unlock_ex(ip);
1441         }
1442
1443         /*
1444          * chain is locked, ip is locked.  Unlock ip, return the locked
1445          * chain.  *ipp is already set w/a ref count and not locked.
1446          *
1447          * (parent is already unlocked).
1448          */
1449         if (ip)
1450                 hammer2_inode_unlock_ex(ip);
1451         *chainp = chain;
1452         if (chain) {
1453                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
1454                 /* already locked */
1455                 return (0);
1456         } else {
1457                 return (EIO);
1458         }
1459 }
1460
1461 /*
1462  * Find the directory common to both fdip and tdip, hold and return
1463  * its inode.
1464  */
1465 hammer2_inode_t *
1466 hammer2_inode_common_parent(hammer2_inode_t *fdip, hammer2_inode_t *tdip)
1467 {
1468         hammer2_inode_t *scan1;
1469         hammer2_inode_t *scan2;
1470
1471         /*
1472          * We used to have a depth field but it complicated matters too
1473          * much for directory renames.  So now its ugly.  Check for
1474          * simple cases before giving up and doing it the expensive way.
1475          *
1476          * XXX need a bottom-up topology stability lock
1477          */
1478         if (fdip == tdip || fdip == tdip->pip) {
1479                 hammer2_inode_ref(fdip);
1480                 return(fdip);
1481         }
1482         if (fdip->pip == tdip) {
1483                 hammer2_inode_ref(tdip);
1484                 return(tdip);
1485         }
1486
1487         /*
1488          * XXX not MPSAFE
1489          */
1490         for (scan1 = fdip; scan1->pmp == fdip->pmp; scan1 = scan1->pip) {
1491                 scan2 = tdip;
1492                 while (scan2->pmp == tdip->pmp) {
1493                         if (scan1 == scan2) {
1494                                 hammer2_inode_ref(scan1);
1495                                 return(scan1);
1496                         }
1497                         scan2 = scan2->pip;
1498                         if (scan2 == NULL)
1499                                 break;
1500                 }
1501         }
1502         panic("hammer2_inode_common_parent: no common parent %p %p\n",
1503               fdip, tdip);
1504         /* NOT REACHED */
1505         return(NULL);
1506 }